Ambulatory typewriter apparatus having only one driving means



June 1965 s. R. PEDERSEN AMBULATORY TYPEWRI'I'ER APPARATUS HAVING ONLY ONE DRIVING MEANS Filed Jan. 16, 1963 4 Sheets-Sheet 1 FIG. 4

INVENTOR. SVEND R. PEDERSEN ATTORNEYS June 22, 1965 s. R. PEDERSEN 3,190,427

AMBULATORY TYPEWRITER APPARATUS HAVING ONLY ONE DRIVING MEANS 4 Sheets-Sheet 2' Filed Jan. 16, 1963 INVENTOR SVEND R. PEDERSEN BY ATTORNEYS June 22, 1965 s. R. PEDERSEN 3,190,427

AMBULATORY TYPEWRITER APPARATUS HAVING ONLY ONE DRIVING MEANS Filed Jan. 16, 1963 4 Sheets-Sheet :5

FIG. 9A

FIG. 8B

INVENTOR. SVEND R. PEDERSEN FIG. 9 B BY ATTORNEYS J1me 1965 s. R. PEDERSEN 3,190,427

AMBULATORY TYPEWRITER APPARATUS HAVING ONLY ONE DRIVING MEANS Filed Jan. 16, 1963 4 Sheets-Sheet 4 INVENTOR sveu o R. PEDERSEN FIG. 90 My ATTORNEYS United States Patent 3,190,427 AMBULATORY TYPEWRITER APPARATUS HAV- ING ONLY ONE DRIVING MEANS Svend R. Peder-sen, Lafayette, Calif, assignor to Pederseu Electronics, Lafayette, Califi, a corporation of (Zalifornia Filed Jan. 16, 1963, Ser. No. 251,858

8 Claims. (Cl. 1972) This invention relates to typewriters of the kind which are adapted to move over a supporting surface while typing directly onto the same surface. More particularly this invention relates to a power train for providing the transport movement to such a typewriter.

Typewriters of the above general style are useful in applying legends, notes, and the like to documents which cannot be conveniently inserted into the conventional carriage of ordinary typewriters. For example, certain large blueprints or drafting sheets are not readily insertable and must be hand lettered. In an attempt to supply this general need, ambulatory typewriters have previously been constructed to move across the print-receiving surface.

Originally, these machines utilized spring motors adapted from existing spring motors found in carriagereturn mechanisms of conventional typewriters. As will be recalled by those having used older conventional port- .able typewriters, these spring mechanisms generated enough mechanical shock between successive strokes that the machine frequently would walk randomly over the supporting table during typing.

When this same style of motor was embodied in an ambulatory typewriter, it caused problems in maintaining a faithful and straight line of advance. Furthermore, the power available to propel the typewriter would decrease as the spring unwound. Thus, attempts were made to improve upon the original motive means.

One effort utilized a compressed gas motor which atternted to avoid the undesirable jarring and shaking caused by spring motors. In this arrangement the type writer was supported on a pair of simultaneously driven endless belts. However, it will be apparent that unless the belts are truly simultaneously moved, such a typewriter will be steered right or left of the intended line of ,printing. Thus, slippage ibetween either of the belts and their associated drive rollers is critical. For example, in an attempt to electrify the motive means, endless chains were substituted for resilient belts, and continuously energized electric motors have not been previously successfully employed.

Slight variations from straight line tracking conceivably might not be entirely objectionable if all lines of type could be limited to the usual 6 /2 inches as found in ordinary correspondence. However, it is not uncommon in ambulatory applications for a line of type to extend many times the above distance, Thus, even slight misalignment presents a critical problem.

In addition to misalignment caused by a differential in slippage in two-belt systems as noted above, I have also observed that a pair of traction belts will seemingly inherently produce unfaithful tracking for another reason. To cause a two-belt drive to move along a precisely straight line for extended distances, the overall diameter of each of the two drive rollers plus their associated belt thicknesses must be continuously identical.

I have observed, however, that both belts will not always be of identical thickness and belt thickness is not always precisely uniform throughout the length of any one belt. Furthermore, previous erasures can cause the coefficient of friction of the supporting surface under one roller to differ from the coefficient of friction of the surice face under the other. Therefore, having in mind these fundamental shortcomings of a two-belt system, I have provided an ambulatory typewriter supported and driven by a single belt which substantially eliminates the above problems.

Therefore, with the foregoing and other problems in mind, it becomes generally an object of the present invention to provide an improved power train for an ambula tory typewriter.

It is another object of the invention to provide an ambulatory typewriter supported and driven by a single belttype traction means.

As mentioned above, continuously energized electric motors have not been previously successfully utilized. Many reasons could exist which might account for this. However, I have observed that a relatively low initial acceleration ought to be built into the lateral advance means. If the acceleration is initiated relatively slowly each increment of lateral movement can be quite quick without causing undesirable jarring.

It is a more particular object of the invention to provide an improved power train including a continuously energized electric motor and an improved support assembly, wherein an accurate straight line of advance is asured.

It is another object of the invention to minimize mechanical shock in an ambulatory typewriter to improve the movement of the typewriter across a support surface.

Another object of the invention is to provide the power train with means for adjusting the impact of a typing element with the print-receiving surface whereby mechanical shock transmitted to the typewriter is minimized as well as improving the quality of printing accomplished.

It is a more specific object of the invention to provide an improved power train wherein relative movement may be selectively arrested whereby composite characters can be printed by successive strokes of the typewriter.

A more specific object of the invention is to provide an improved power train incorporating improved means for varying the increment of typewriter advance, whereby lost motion is substantially eliminated which otherwise would contribute to transmitting mechanical shock to the typewriter.

These and other objects of the invention will become more apparent from the following detailed description of a preferred embodiment when taken in conjunction with the accompanying claims and drawings, in which:

FIGURE 1 is a perspective view of a typewriter according to the invention;

FIGURE 2 is a bottom view of the typewriter repre sented in FIGURE 1 showing a support assembly thereof;

FIGURE 3 is an elevation view along the line 3-3 of FIGURE 2 showing the traction'belt drive means of the typewriter represented in FIGURE 1;

FIGURE 4 is an elevation view along the line 4-4 of FIGURE 2 showing a vertically adjustable ball support portion of the support assembly;

FIGURE 5 is a partly diagrammatic perspective view showing the drive and key mechanism for activating a typical key and for advancing the typewriter to a new print position;

FIGURE 6 is a perspective drive pulley detail view;

FIGURE 7 is a perspective variable advance control detail view;

FEGURES 8A through 8D disclose a side elevation detail of the sequence of movements of a type key linkage;

FIGURES 9A through 9D disclose in side elevation the detail of a sequence of movements of the drive linkage for advancing the typewriter across a support surface;

FIGURE 10 is an end view along the line 10-10 of FIGURE 3;

on the surface.

FIGURE 11 is a detailview ot a portion of the variable.

writer having motive means for intermittently advancing the typewriter along a line of typing in response to actuii be applied to the belt in order toderive anaccurate line of movement for the typewriter. Accordingly, as shown in FTGURES 2 and 3, an elongated backing member 35 member 35 is of. relatively stiil resilient material which ation of the typewriter keys. In addition to a motor the power train includes a transport assembly compr sing a single endless belt and a rotatable sphere carried below the typewriter and disposed to one side of the belt. The belt and sphere are both arranged to engage the supporting surface so as to share, (unequally) the weight of the typewriter. By adjusting .the vertical position of the justed. My power train further includes means for adjusting the degree of each increment of lateral advance as well as means for arresting the advance entirely.

' FIGURE '1 shows an ambulatory typewriter 10 having a number of keys 11 arranged to form a keyboard 12. Typewriter 10 includes an array of typing elements .13

. disposed to form a downstrike segment assembly whereby each element strikes the supporting surface in the region 'of a common imprinting center 14. Imprinting center 14 is defined by a substantially'oblong shaped opening.

15 formed ina transparent alignment member or template 16. Template 16 is carried by the typewriter and inscribed so as to aid in alignment of the typewriter. While activation of any of keys 11 will serve to operate the elements 13, it also will provide a lateral advance of the typewriter across the supporting surface after impact of the type face Support assembly sphere thetype face impact on the surface can be adcan be twisted longitudinally; For example, linen based Bakelite is quitesatisfactory. I As shown bestfin FIGURE 3, member 35 is supported by and spaced from plate by pairs of adjustable standof! posts 37. Posts 37 for example, can be formed simply by using screws with washers of selected thickness interposedgbetween member '35 and a horizontal rear edge portion 38 of plate 25." Thus, it will be readily evident that member canbe shimrned at each of posts 37 "in order to apply an "appropriate, twist which will derive an accurate-straight line of advance for the typewriter.

Means are also provided for properly tensioning the belt (FIGURE 3), wherein a broad leaf-spring 39 is disposed to upwardly urge the upper reach 21 of belt 17. Spring 39 is secured to the rear edge portion 38 of plate 25., 1

As noted above the belt 17 isdisposed to underly a position located slightly to the front of. the machine from the center of gravity thereof- Accordingly,belt 17 carries a substantial portion of the weight of, the typewriter. The

weight of the typewriter, however, is shared by a ball- Beneath the typewriter and" attached to the side frame 'thereof a tractor base plate 25 wide segment assembly base plate 26 are disposed to generally receive the weight of the typewriter. Plates 25, 26 each'are substantially flat members which function as a bottom frame for the typewriter. At the frontedge of plate 25 a pair of tabs 27, 28 are bent downwardly and aredrilled to format journal for a pair of axles 29 and 3%, respectively. which belt 17. Belt 17 is suiiiciently close to the keyboard edge of the typewriter to prevent tipping the typewriter by the a downthrust of a typists finger action. However, it is also close enough to the projected center of gravity to,

carry most of the weight of the machine and produce a straight line of advance. Belt 17 has'a lowerand upper reach respectively designated 20 and '21. The backside of belt 17 is formed witha number of teeth 22 which engage corresponding detents 23 formed: in each ofrollers 18, 19.

Roller 18 is mounted for rotation on axle 29 and' re- 'tained thereon by. a snap ring. Roller '19 is mounted -on axle 30 for rotation in one direction only. Suitable unidirectional clutch means for preventing reverse rotation of roller 19 with respect toaxle 3d are not shown {as such means are believed well known in the art' and can be enclosed within a roller'19. Roller-19 is retained a socket assemblyr il. I

7 Impact adjustment Sphere 4% depends downwardly to engage the support ing surface beneath the typewriter. The predetermined distance'jwhich sphere'40 extends'below plate 26 is adiustable whereby the impact .of a typing element striking the printing surface may be varied. As shown, sphere 4% is carried by a cylindrically shaped plastic member 42 'closed at one end and open at the other. Member 42 has exterior threadsand an interior recess 43'. The open end of'recess 43 is turned'inwardly to retain the sphere 49. Member 42 is tlneadably received ina flangedmounting member 45. 'Member 45 includes a cylindrical portion 46 which extends through an opening in plate 26. Member "45 is secured to plate 26 by means of screws as shown in FIGURE 4.

l Means are further provided to lock member tz in place.

Thus, as shown in FIGURES 2 and 4, a groove 47 is a member 42 to lock same in place.

formed around the periphery of member 45. A snap ring 48 fits within groove 47 and isv formed with a tip 49 bent to'extend radially a shortvway into a substantially radial hole drilledthrough member 45. A pointed pin 50 rests loosely in theradialihole wherebyinsertion of the tip 49 forces the pin Shinto engagement with the threads of When it is desired to change the vertical position of member 42, tip 49 is withdrawn 'from behind pin 50 and member-.42 screwed vertically by means of the wrenchreceiving detentsSl tormedin the end thereof.

Motive means are provided including a drive linkage serving to intermittently establish an operative driving connection betweenga' continuously energized electric mowhereby aminimum' of mechanicalshock is developed.

on the end of axle 36 by hub member 33', and the' latter V is providedwith alever arm.34. :Hub mem'ber 33 and the typewriter.

' Means are provided wherein an adjustable twist can.

17 in order. to move" tor and the transport assembly in response to operation of the typewriter keys. This motive means includes in general a continuously operative motor means and means for momentarily clutching in to same in a manner Continuously operative power The co'ntinuouslydriven portion of the apparatus includes an electric motor 52 connected in a suitable man 7 nor to the' on-off switch 53 shown in FIGURE 1. The armature of motor 52 continuously drives an output shaft 54 which carries a suitable centrifugal clutch assembly 55. Clutch assembly 55 picks u'p a driving pulley 56 as it gets ';up to speed. Speed reduction pulley means 57 are belts 63, 64 are momentarily extended lengthwise.

former will aid in understanding of the latter. the type bar linkage will be described first.

mounted for rotation on a stub shaft 58. A driven pulley 59 is fixed to the end of a snatch roller 61 Roller 66 is formed with a plurality of axially extending notches 60a. The function of snatch roler 64 is more fully explained below.

Pulley means 57 is arranged to absorb a substantial portion of any shock encountered when a key is actuated and a pawl momentarily interposed into the continuously operative motive means. Accordingly, pulley means 57 comprises a pair of sheaves 61, 62 mounted to be rotate about a common axis and disposed in contiguous side-byside relation. Each of sheaves 61, 62 is formed of a pair of independent halves 61a, 61b and 62a, 62b. The ad jacent halves 61b, 6212 are fixed to rotate together and are free to move together along stub shaft 58 both toward and away from their respective other halves 61a, 62a. Readily stretchable belts 63, 64, such as of rubber, are respectively trained between the drive pulley 56 and sheave 61, and driven pulley 59 and sheave 62. The peripheral edges of each pair of sheave halves can be beveled in order to form a V-shaped channel and the belts preferably formed with an annular cross section, either circular or oval in shape.

I have observed that low initial acceleration results from employing the stretchable belts with the above sheaves. Thus, when pawl 185 (described below) is interposed into roller 60, the upper reaches 63a, 64a of Rubber belts which are readily compressible provide some additional absorption due to lateral compression by the sheaves since the belts tend to momentarily wedge themselves resiliently into the V-shaped channels. Thus, shock directed to the driven pulley 59 is absorbed to a great extent in pulley means 57 without being further transmitted to belt 17.

Intermittent driving connection Means are provided for intermittently advancing belt 17 responsive to actuation of a key 11, or the space bar 147.

While FIGURE 5 shows an overall perspective view, the detail views of FIGURES 8A through 8!) illustrate the structure and sequence of operation of a type bar actuating linkage. FIGURES 9A through 9D show the structure and sequence of operation of the drive linkage which serves to advance the typewriter. Since there is a certain similarity in these two linkages, description of the Therefore FIGURE 8A demonstrates an at rest condition. In FIGURE 83 a key has been depressed and the pawl 195 interposed. FIGURE 8C shows application of power to the linkage and FIGURE 8D a return to an at rest condition but with a key still depressed.

FIGURE 9A is at rest for the lateral advance linkage. FIGURE 93 shows cocking of the advance linkage during forward movement of a typing element 13. FIG- URE 9C shows interposing a lateral advance pawl 205 responsive to return movement of a typing element 13, and FIGURE 9]) shows application of power to the linkage to advance the typewriter an increment of lateral displacement.

Typing elements 13 (FIGURE 5) are disposed on the ends of the type bars 67 for down-strike actuation. Bars 67 are operated through levers 68 and 69 by a downward pull on pull-rods 7 0.

Type bar linkage In understanding the type bar actuating linkage of FIGURES 8A through 81) it can be observed generally that snatch roller 60 supplies the power or motive force to operate typing elements 13. Each of keys 11 serves to interpose a related pawl 105 into one of the notches 60a of snatch roller 6t}. Continued rotation of the latter then applies the downward pull to pull-rod 7 it.

Having in mind these general objectives the specific structure can be described wherein the type bar actuating linkage is designated generally by the reference numeral 71. Linkage 71 includes a key unit 72. Key unit 72 includes a key 11 having downwardly depending stem 73. Stem 73 is formed with an L-shaped extension having an upper edge urged upwardly against a resilient pad 74. Stem 73 is pivotally connected by a rivet 75 to a generally crescent-shaped member 76. Member '76 is mounted to be pivoted about a rod 77 extending transversely of the keyboard 12. Member 76 is spring loaded counterclockwise by a spring 78 connected just below rod '77 on one end and connected at its other end to a spring anchoring plate 79 carried by a transversely extending rod 89 extending across the width of keyboard 12. The lower end of member 76 carries a latch crank 81 pivoted thereto by a rivet 82. Crank 81 has a short transversely extending portion 83 which projects into a hole 84 in member 76. A spring 85 urges portion 83 against the left edge of hole 84. Latch crank 81 is further provided with an upwardly extending finger 86 formed at its top with an L-shaped seat 87.

Key unit 72 is operated by downward movement of key 11 which carries finger 86 upwardly as shown in FIG- URE 8B. Release of key 11 returns finger 86 to its lowered position and returns key 11 upwardly until arrested by pad 74.

Upward movement of finger 86 serves to operate an interposer unit designated generally as 90. Unit 94 includes a T-shaped rocker 91 having three arms 92, 93, 94. Rocker 91 is pivoted by a rivet 95 through a some what U-shaped bell crank 96. Arm 93 has a short transversely extending portion 93:: which is disposed to be received onto seat 87. In operation, upward movement of finger 86 will rotate rocker 91 counterclockwise about rivet )5. A counteracting spring tension is applied by a spring 97 connected between arm 92 and a latch member 98 pivotally carried on a downwardly extending arm 161 of bell crank 96. Member 98 is formed with a rounded detent surface 99.

Bell crank 96 also carries an interposer plate 102 pivotally mounted thereto by a rivet 103. At the top of plate 132 there is formed a pawl adapted to be moved into engagement with any of notches 6011 when plate 192 is rotated clockwise about rivet 103. In order to rotate plate 162, the end of rocker arm 94 is upwardly curved and received in a recess 166. Upward movement on arm 93, imparted by actuation of key 11, serves to move pawl 105 into snatch roller 69. Positive entering action of pawl 195 is assured by rounded detent surface 99 which contacts with a corresponding surface on plate 102. The movement of latch member 98 is in the nature of an over-center spring movement which insures positive engagement once appropriate movement is initiated.

Clockwise movement of plate 102 is arrested after pawl 105 is inserted into snatch roller 69. Thus a short, transversely extending interposer stop dog 167 formed integrally with bell crank 96 is received by a recess 158 formed in plate 102. Each interposer unit 96 pivots generally about a rod 1% extending transversely of the. keyboard through hell cranks 96. Counterclockwise rotation thereof acts against tension of a spring 1% con nected between each crank 96 and a fixed member 114.

By interposing a selected pawl 105 into snatch roller 66 the snatch roller will drive the selected unit 99 counterclockwise about rod 1%. During this counterclockwise movement pawl 105 moves downwardly until it is disengaged from roller 69, meanwhile actuating pullrod 70.

Space bar operation is provided by means of a link in similar fashion, but without a typing element 13 connected thereto. Further explanation is not consid ered necessary in View of the foregoing description of a typical linkage 71.

' anchor stud- 113.

, surfaces.

' and lever arm 34.

7 Lateral advance linkage Means are provided whereby the lateral advance of the typewriter responds to operationot a selected type bar actuation linkage 71. Accordingly a bail assembly comprised ofa pair of bail levers1ii9'a and 19% carrying a transverse bail 110 secured in the upper ends thereof, pivots about rod 190. Bell crank 96 is further provided with a bail drive extension portion 111 which is disposed V to apply counterclockwise movement of bail levers 199 during downward movement of pawl 195. The bottom by a side plate 126 or part of the frame.

of lever 109a is connected by a spring 112m a spring 7 Spring 112 servesto 'load bail 116 against extension portion 111. Operation of any oneof keys 11 causes bail 110 to be carried ina direction toward the imprinting position 14. .Upon disengagement of pawl 105, typing element 13 continues to move rerward by inertia until it strikes a resilient wire 117 (FIG-,. URE 12) mounted to and extending across and above a bifurcated guide finger 118. Finger 118 is disposed about imprinting position 14- and serves to guide each ele ment 13. therethrough until it strikes the print-receiving At that time wire 117 has been depressed and serves to rebound the element 13 upwardly until spring 104 takes over, asis conventional. Spring .112 assists by moving bail 110 clockwise against extension portion 111. V

The means provided for interrelating operation ofa typing element and lateral advance of the typewriter further includes .a stiff Wire link 115 carried at the lower end of bail lever 109a as shown in FIGURE 5. Link 115 drives a generally crescent-shaped member 176 which is similar in construction to member'x76 of FIG- URES 8A-8D. 7

Where components are utilized in the lateral advance linkage,.which are somewhat similar to components in the type bar actuating linkage 71, reference numerals relating thereto will be hereinafter designated by increasing their value by 10% Thusthe reference numeral for member 76 as shown in linkage 71 resemblesmember 176 of the lateral advance linkageshown in'FlGURES 9A" 9]). Of course where the same structure is shared by 121 receives the end of lever 34 so that it can rotate axle 39. The clutch means within roller 19 is arranged where- 'by the roller 19 is driven only by upward movement of lever 34. Downward movement. of lever34, effected by spring 1 16, rotates axle to return link 120 downwardly.

Means for va-rying'the vertical movement of link 120 to adjust the increment of displacement of the typewriter includes a. channeled lever arm 122 having a groove 129 therein. Arm 122 has. transversely bent ends 123 and 124 and pivots about a support, such as stud 125 carried End 123 is connected 'bya' pull-rod 170 f-o-r'ydo'wnward movement effected by bell crank 196 "(F-IGURES9A-9Dy Arm 122' is spring loaded against such movement by aspring "127 which connectsend 124 to side plate 126.

The upper. end bf drive linkv 120 is arranged to be movedlongitudinally of arm 122. 'A l-shaped follower plate 1% slides along groove 129 and includes a slot135 to receive'studl125. A. hole 128 is adapted to be connected to the upper end of drive link 120 such as by a loosely fitting rivet whereby-link 120 can pivot about same. a I I The upper] end of link 120 can bemoved along arm 122 by a knurled knob 131 rotatably mounted on' a stud 13 2. Knob 1:3-1is conveniently located adjacent the keyboard and is adjustable therefrom. T he side of knob 131 is provided with a fiace cam 163. A cam follower in the form of a stud 134 projects from the side'of a cam fol lower connecting member135n Member 135 is carried the two linkages, as for example spring anchorplate 79,

the reference numeral will be the same in both instances.

Finger 186, as best shown in FIGURE 9, is normally carried so that portion 193a rides'along the side thereof as distinguished from resting in seat 187. Movement of bail counterclockwise as shown in FIGURES 9A 9D'by actuation of any of keys 11 serves to drive link to'the right thereby pivoting member'l'l' about rod 77. This action moves finger lidfidownwardly whereby portion 193a slips onto the seat 187. In this condition the lateral advance linkage is conditioned substantially as shown in FIGURE 9B so that as movement of bail 110is reversed (by disengagement 0t pawl 1435 from roller 60)- finger 186 will be driven upwardly to interpose pawl 265 into roller 60. A pull-rod 17i is connected to be pulled downwardly by counterclockwise rotation of bell crank 196.

Adjustable character spacing at one end by stud 132 which extends through an elongated slot 136 in member 135. At the other end mem- 1 er is carried by a rivet through the upper end of tially eliminated so that various character spacings can be selected without further contributing to mechanical jarring of the typewriter during operation. 7

Itshould be noted that as the upper end of link 120 is moved along arm 122lever arm 34 receives substantially no adjustmentuntil link 12% is pulled upwardly, Ac-

cordingly, thevariable advance can be adjusted between -characterswithout moving the traction means during adjustments of the moment arm. Such adjustments can be made both'to increase as wel'l'as decrease theamount of 1 spacing between characters.

Means are provided for. transmitting the downward I movement of pull-rod into. an adjustable incrementalf lateral movement of the typewriter. Asj noted above;

lateral movement of the typewriter is effected by means of rotation of axle 39 ca-used'byupward movement of a lever arm 34 (FIGURE 2).- As also previously noted suitable unidirectional clutch means is interposed between axle 30 Means for converting downward pull of rod 170 to an adjustable upward movement of lever arm 34 comprises generally means for adjusting a moment arm of the lever,

so as to vary the lateral typewriter displacement. This is best shown in FIGURE 7 where a drive link 1213 is formed with an elongated hole 121 atits lower end. 'Hole 7' of the typewriter by Lateral advance arresting means While means, as just described, have been provided for varying the degree of advance of the traction means, there is also provided means for temporarily preventing advance altogether "of the typewriter between successive strokes of same. The control of suchrneans is manually operable fromthe keyboard, such as by' an-arresting button 138 (FIGURE 5). In general, the mechanism for completely arresting relative movement between the typewriter andt-he printing surface, functions by momentarily precluding the leftward return of the bottom of bail lever 109a as shown in FIGURE-9B,, Release of the arresting button 138 impartsan incremental lateral displacement permitting levers 109 to be moved clockwise. a I

As shown in FIGURE 5 arrestingibutton 138 is mounted upon the top of. a vertically disposed shaft 139 slidably 1 held in a sleeve l itl. The bottom end of. shaft 139 rests upona flat transverse portion of a bail'lever retaining arm 1 41, Bail lever retaining a-rm 14 1 rotates about a point 14 2. wRet-aining' arm 141 .is'f-ormedfwith .a short, transversely extending tab 143. The broad outer surface of tab 143 is disposed to move in an arc whereby it can be brought into engagement with the edge of bail lever 109a by downward movement of shaft 139. Engagement between tab 143 and bail lever 109a serves to hold bail lever 109a from clockwise return movement as shown in FIG- URE 913. During normal operation tab 143 is disposed out of engagement with bail lever 109.

Thus by manipulating button 138 composite characters can be formed. For example, while holding button 138 depressed an O can be struck followed by a slant line thereby forming the character for theta. Subsequent release of button 138 advances the typewriter by releasing bail 110.

In order to feed .a ribbon (not shown),- any suitable means can be utilized As noted above a bail lever 169 is located at each end of bail 110 for pivotal movement about rod 100. Movements of the bottom end of bail lever 10% can be utilized to impart the necessary incremental advance to a ribbon feedmechanism as by means of a ratchet operated by link 149.

Suitable supply and take-up rolls for the ribbon feed can be provided beneath plate 25 and fed in conventional manner to the imprinting center 14 for typing. For example, the elongated holes 144 can be utilized to carry a suitable ribbon guide to direct a ribbon across imprinting center 14.

From the foregoing description it will be evident that I have provided an improved drive train arrangement having many desirable features. My drive train arrangement operates to produce faithful straight line tracking. This tracking can be momentarily arrested entirely or, the increment of lateral advance can be increased or decreased as desired. My drive train arrangement achieves the above faithful tracking while employing continuously operative mot-or means as distinguished from previous impractical schemes.

While there has been shown and described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the apparatus illustrated and in its operation may be made by those skilled in the art, without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

I claim:

1. In a typewriter of the type which is adapted to move over a print-receiving surface, and which has a driving power train including motive means for intermittently advancing the typewriter in a predetermined direction across the surface in response to typing thereon, a transport assembly comprising a frame disposed to generally receive the weight of the typewriter, a pair of rollers driven by the motive means and spaced apart in a direction corresponding to the direction of movement of a line of typing, a single endless belt trained around said rollers for cyclic movement to move said typewriter in said direction, said single belt being the sole traction means for said typewriter, said belt serving to support said frame from said print receiving surface, and a rotatable sphere carried by said frame to continuously engage said surface to support the typewriter during typing upon said surface, said sphere being disposed laterally to one side of said belt and extending downwardly beneath said typewriter sufficiently whereby the weight of the typewriter during typing is transmitted to said surface via said belt and said sphere.

2. Typewriter apparatus as defined in claim 1 further including means serving to vary the impact with which the type faces of the typewriter strike the supporting surface including means for adjusting said predetermined distance.

3. Typewriter apparatus as defined in claim 2 wherein said sphere is disposed between said belt and an imprinting position common to the typing elements of the typewriter, the sphere being adjacent the latter whereby the impact of printing is rendered adjustable.

4. In a typewriter of the type which is adapted to move over a print-receiving surface, and which has a driving power train including motive means for intermittently advancing the typewriter in a predetermined direction across the surface in response to typing thereon, a transport assembly comprising a frame disposed to generally receive the weight of the typewriter, a pair of rollers driven by the motive means and spaced apart in a direction corresponding to the direction of movement of a line of typing, a single endless belt trained around said rollers for cyclic movement to move said typewriter in said direction, said belt serving to support said frame from said print receiving surface, said =belt including an upper and a lower reach, the lower reach being disposed to engage the printing surface, and an elongated backing member having a groove therealong serving to receive the back side of said lower reach, said backing member being supported by and spaced from said frame by pairs of adjustable standoff posts disposed to the sides of said lower reach whereby an adjustable twist can be applied to said member to derive an accurate line of movement for said typewriter, and a rotatable sphere carried by said frame to one side of said belt and disposed to extend downwardly beneath said type-writer a predetermined distance to engage said surface whereby the weight of the typewriter is transmitted to said surface via said belt and said sphere.

5. Typing apparatus -as defined in claim 4 further including means for tensioning said belt comprising a broad leaf-spring arranged in sliding contact engagement with the back side of the upper reach of said belt.

6. In a typewriter having keys arranged to form a keyboard and an array of typing elements arranged to strike a printing surface at a common imprinting center upon activation of said keys, said typewriter being further of the type which moves over said print receiving surface, the combination comprising endless belt type traction means trained to be cyclically driven to move said typewriter across said surface in a predetermined direction corresponding to the direction of progress of said printing, continuously energized electric motor means, means for establishing an operative driving connection between said motor means and said traction means responsive to operation of said keys, and means in said driving connection for absorbing substantial shock in establishing said driving connection, the last said means including a driving pulley, a driven pulley, and reduction pulley means, said reduction pulley means comprising first and second sheaves mounted to be rotated about a common axis and disposed in contiguous side-by-side relation, each of said sheaves being formed of a pair of independent halves, the adjacent halves of said sheaves being fixed to turn together about said axis and free to move along said axis toward and away from their respective other halves, and resilient readily stretchable belts respectively trained between said drive pulley and said first sheave and between said driven pulley and said second sheave.

7. A typewriter apparatus as defined in claim 6 wherein the peripheral edges of each pair of sheave halves are beveled to form a V-shaped channel, and wherein said resilient belts are of readily compressible annular cross section.

8. In a typewriter having keys arranged to form a keyboard and an array of typing elements arranged to strike a print receiving surface at an imprinting center common to all said elements, and wherein said imprinting center is arranged to move relative to said surface between successive strokes of said keys, motive means serving to provide said relative movement, and means for establishing an operative driving connection from said motive means to provide said relative movement, and means in said driving connection for absorbing substantial shock in establishing the driving connection, the last said means including a driving pulley, a driven pulley, and reductio n' pulleyl means, said reduction pulley means comprising first and second sheaves mounted to be rotated about a common axis and disposed in contiguous side-by-side relation, each of said sheaves being formed of-a pair of independent halves, the adjacent halves of said sheaves being fixed to turn together about said axis and free to move along said axis toward and away from their respective other halves, and resilient readily stretchable belts respectively trained between said drive pulley andsaid first sheave and between 1 said driven pulley and said second-sheave.

ROBERT E.

Crowell 19d783 Palmer et a1 197-2 PULFREY, Primary Examiner. 

1. IN A TYPEWRITER OF THE TYPE WHICH IS ADAPTED TO MOVE OVER A PRINT-RECEIVING SURFACE, AND WHICH HAS A DRIVING POWER TRAIN INCLUDING MOTIVE MEANS FOR INTERMITTENTLY ADVANCING THE TYPEWRITER IN A PREDETERMINED DIRECTION ACROSS THE SURFACE IN RESPONSE TO TYPING THEREON, A TRANSPORT ASSEMBLY COMPRISING A FRAME DISPOSED TO GENERALLY RECEIVE THE WEIGHT OF THE TYPEWRITER, A PAIR OF ROLLERS DRIVEN BY THE MOTIVE MEANS AND SPACED APART IN A DIRECTION CORRESPONDING TO THE DIRECTION OF MOVEMENT OF A LINE OF TYPING, A SINGLE ENDLESS BELT TRAINED AROUND SAID ROLLERS FOR CYCLIC MOVEMENT TO MOVE SAID TYPEWRITER IN SAID DIRECTION 